Existing liquid delivery module tank systems, such as for automotive fuel or diesel emissions fluid, is an integrated system that combines a combination of a pump, fluid reservoir, in-tank suction filter, an optional bracket assembly, leveling springs, a pressure regulator, a liquid level sender assembly and a pressure filter, into a single unit that is positioned at the bottom inside of the tank. One example is the fuel delivery module system used for automotive fuel located inside the fuel tank. The fuel pump is situated inside a hard body reservoir structure and flows fuel from the inside of the hard body reservoir and supplies the fuel through it from the fuel tank to the engine. An in-tank fluid filter is positioned inside the hard body reservoir and has a filter body made of porous material with an attached plastic outlet port for connecting the filter to an inlet fitting on the fuel pump. The outlet port of the filter has a flow axis defined by an intended direction of fluid flow from the filter to the pump. The in-tank suction fluid filter is used to filter the fuel present in the fuel tank prior to entering the fuel pump. This filter is described with the term suction because the pump acts as a suction to pull fuel through the filter. In some embodiments there is a second filter positioned at the outlet of the fuel pump which filters fuel coming out of the fuel pump and before the fuel enters the engine. This filter is often referred to as a pressure side filter because the pump develops pressure against this filter to push fuel through the pressure side filter.
The hard body reservoir is a plastic molded or metal canister that contains the in-tank suction fuel filter and fuel pump and acts as a holder of fuel to maintain a constant supply of fuel to the fuel pump. The design of the reservoir improves drivability during dynamic handling conditions by maintaining a supply of fuel for the fuel pump. An example of such a reservoir is disclosed for a fuel delivery module in U.S. Pat. No. 5,665,229, the disclosure of which is incorporated herein by reference. The reservoir adds to manufacturing costs by requiring additional human labor and material.
The fuel delivery module needs to rest on the bottom of the fuel tank to be in contact with the fuel at the bottom of the tank to accommodate for low fuel conditions when the amount of fuel in the tank is at its lowest. The fuel tank height will increase or decrease with thermal expansion as temperature and pressure changes inside the tank. The fuel delivery module must be able to accommodate this tank height change to maintain contact with the bottom the tank. Current designs utilize height adjusting springs in the fuel delivery module to allow the module to expand and contract with the tank height change. The springs are placed under a constant compressive load when the fuel delivery module is installed into the fuel tank and the springs can extend up and down to expand or contract the height of the module as the fuel tank height changes.